An upgrade step is available in case of having an existing site with the experimental0.1 plone.multilingual version::

>>> from plone.multilingual.upgrades.to02 import upgrade

.. note:: You must reinstall the plone.multilingual package in order to install the required new utility in place before upgrading. If you are using a version of Dexterity below 2.0, you must install the package plone.app.referenceablebehavior and enable the *Referenceable* (plone.app.referenceablebehavior.referenceable.IReferenceable) behavior for all your Dexterity content types before you attempt to upgrade your site.

You can run the @@pml-upgrade view at the root of your site or follow the upgrade step inportal_setup > upgrades. If you can't see the upgrade step, press *Show old upgrades* andselect the *Convert translation based intids to uuids (0.1 → 02)*

- Do not raise a KeyError when registering or adding a language independent translation. [maurits]

- Take account on the use case where user could do and do changes on the translations groups and its members. Be sure that it does not leaves any traces of orphan objects in the storage. [ramon, sneridagh]